Chronic obstructive pulmonary disease (COPD) is one of the respiratory diseases and is a disease accompanying airflow obstruction in addition to chronic bronchitis, emphysema, or the complications of both diseases, and characterized by airflow limitation which is not completely reversible. Smoking or the like triggers inflammation of the bronchus or collapse of alveoli. As a result, symptoms such as cough, sputum production or shortness of breath appear, and when the disease progresses, hypoxemia will be developed. As an agent for treating COPD, a bronchodilator (for example, an anticholinergic drug, a β2-stimulator, a xanthine derivative or the like), an expectorant, a steroid or an antibiotic is used. With the use of a bronchodilator or an expectorant, improvement of the symptoms can be expected, however, they are not agents that fundamentally improve the pathological conditions. Additionally, long-term dosing of a steroid is not preferable in terms of side effects or the like. Accordingly, a safe and useful therapeutic agent for COPD has been demanded.
It is known that the compound described in WO03/74483 (Patent Reference 1) has EP2 agonist action and is useful for prevention and/or treatment of pulmonary injury, pulmonary fibrosis, pulmonary emphysema, bronchitis, chronic obstructive pulmonary disease etc.
However, since EP2 agonist acted on organs besides the respiratory organ, for example circulatory organs, there was fear that it lower the blood pressure of the patient having the normal blood pressure.
[Patent Reference 1] WO2003/74483